RELATION TO CO-PENDING APPLICATION
This application is related to co-pending application Ser. No. 08/362,643, filed Dec. 23, 1994.
1. Field of the Invention
The present invention relates to an improvement in a position pointing device used in combination with a position detecting device employing electromagnetic waves.
2. Description of the Related Art
Prior to the instant application, the applicant has proposed, in Japanese Patent Application No. 61-213970 (Japanese Patent Laid-Open No. 63-70326), a position detecting device in which a sensing section exchanges electric wave signals with a position pointing device so as to detect the coordinate value of a position pointed by the position pointing device.
Briefly, the position detecting device disclosed in Japanese Patent Laid-Open No. 63-70326 has a plurality of loop coils constituting the sensing section and adapted to transmit an electric wave of a predetermined frequency. The electric wave is received by a resonance circuit provided in the position pointing device so that resonance takes place in the resonance circuit to emit electric wave. This electric wave is received by the loop coil so that a voltage is inducted in the loop coil. This operation is conducted successively on the plurality of loop coils constituting the sensing section, so that the coordinate value of the position pointed by the position pointing device is determined based on the levels of the voltages induced in the loop coils.
The position detecting device of the type described faces a demand for the ability to enter various kinds of information in addition to the coordinate value of a pointed position, such as information which indicates that the position pointing device, e.g., a pen or the like, has been set to a position for pointing a definite position (this state will be referred to as "pen-down state," hereinafter), information concerning the type of the position pointing device, e.g., a pen, a cursor or the like, as well as a demand for inputting, together with the coordinate values, information for continuously varying values of parameters other than the coordinate information, such as, for example, thickness or width of a line and hue or density (brightness) of the position or area appointed by the pointing device.
To cope with such demands, the position pointing device disclosed in Japanese Patent Laid-Open No. 63-70326 employs a manual switch which selectively connects, to the resonance circuit which is constituted by a coil and a capacitor, an additional capacitor so as to slightly vary the resonance frequency, the slight variation in the resonance frequency being detected as a variation in the phase angle so as to be used as information indicative of the aforesaid various types of information.
In Japanese Patent Application No. 63-316943 (Japanese Patent Laid-Open No. 2-162410), the applicant also proposed a position detecting device and an inputting pointing device therefor having a capacitance-variable capacitor (variable capacitor) which is turned as a knob provided on the top end of a penholder turns, causing the capacitance thereof to vary continuously, so that the resonance frequency also continuously varies in accordance with the turning angle of the variable capacitor, the continuous change in the resonance frequency being detected as a continuous change in the phase angle to be used as information for continuously varying the parameter.
In the device according to the aforesaid Japanese Patent Laid-Open No. 2-162410, however, the range, over which the resonance frequency varies as the capacitance of the capacitance-variable capacitor varies coincides with the range (about -60.degree. to about +60.degree.) over which such variations in the resonance frequency can be detected. For this reason, only rough information on a pointed position, the color of a specified area, etc. can be entered, such rough information being typically represented by the input of information on which one of a plurality of preset colors (e.g., red, green, blue, purple, sky blue, brown, white, gray, bright red, bright green, bright blue, bright purple, bright sky blue, yellow, bright white, and black). Thus, the device is not capable of enabling the input of detailed information concerning a plurality of factors which define a color, such detailed information including the one concerning a hue, brightness and chroma, and detailed gradation information, e.g., 256 gradations, of basic colors such as red, green, and blue.
To solve the problem described above, there is a method available, whereby a menu for setting such information on a display screen is displayed, so that an operator may select and set using the position pointing device. This method, however, does not enable the operator to define colors only through the position pointing device, presents a drawback of poor man-machine interface.